Transducer leads



March 10, 1959 e. c. TIBBETTS TRANSDUCER LEADS Filed on. 29. 1954filmy/afar i xi 6 or 862]? 9% MW United States Patent 2,877,363TRANSDUCER LEADS George C. Tibbetts, Camden, Maine, assignor to TlbbettsLabigratorles, Inc., Camden, Maine, a corporation of Ma e ApplicationOctober 29, 1954, Serial No. 465,679 2 Claims. (Cl. 310-91) Thisinvention relates to transducers of the type comprising anelectrostrictive, piezoelectric or other slab which changes dimensionsbetween two points in response to electrical forces, for use inconverting electrical energy into mechanical vibrations or vice versa.In order to conduct current to and from the slabs it is customary tofasten sheets of conducting material over the sides of the slab withparts of the sheets extending beyond the edges of the slab forconnection to an exterior circuit. Usually the slabs are coated with athin layer of conducting material, such as gold foil or graphite, beforethe conducting sheets are applied. In order to get good conductivitybetween the slab and sheets it is necessary to press them firmlytogether. It has also been proposed to strike up parts of the sheet toform edges which are embedded in the slab when the parts are pressedtogether. However, owing to the fragile structure of these slabs it hasnot been possible to obtain good conductivity between the sheets and theslab without damaging the slab.

Objects of the present invention are to provide a device of thecharacter referred to in which good electrical contact between theconducting sheets and slab can be secured without damage to the slab,which is simple and economical in construction and which is durable andreliable in use.

According to the present invention the sheet of conducting materialwhich conducts current to and from the slab is bent into a series ofridges and valleys extending parallel to the slab so that the summits ofthe ridges are held against the slab when the parts are pressedtogether, thereby obtaining good conducting contact between the sheetand slab without danger of injuring the slab. The sheet is preferably inthe form of an elongate strip of metal foil having the ridges andvalleys extending crosswise of the strip. While the strip may be made ofany yielding conducting material, it is preferably made of silver aboutone mil thick. Thus when the parts are pressed together the ridges andvalleys flatten out more or less.

For the purpose of illustration a typical embodiment of the invention isshown in the accompanying drawings in which Fig. 1 is a view of theparts in spaced relationship;

2,877,363 Patented Mar. 10, 1959 Fig. 2 is a plan view of the assembledparts; and

Fig. 3 is a section on line 3-3 of Fig. 2.

The particular embodiment of the invention chosen for the purpose ofillustration comprises two piezoelectric slabs 1 coated on theiropposing faces with gold foil or other conducting material and theconducting strip 3 having a series of ridges and valleys 4. As shown inFig. 3 the two slabs are held together by cement 5 and in laminating theparts together the corrugated strip is flattened by pressing the partstogether, thereby pressing the summits of the ridges into good contactwith the slabs without danger of injury to the slabs. Current may beconducted to and from the other faces of the slabs in any suitablemanner and the slabs may be connected to any suitable vibrating memberas disclosed for example in my co pending application Serial No. 465,597filed on even date herewith.

It should be understood that the present disclosure is for the purposeof illustration only and that this invention includes all modificationsand equivalents which fall within the scope of the appended claims.

I claim.

1. A piezoelectric transducer comprising a crystal slab which changesdimensions between two points along a vibrating face in response toelectrical forces, a sheet of yielding conducting material along saidvibrating face, and means for holding the sheet against the said face,characterized in that the sheet has a series of ridges and valleys, saidseries extending parallel to said vibrating face with smooth, roundedarched portions held in partially flattened, yielding contact with saidvibrating face so as to permit lengthwise flexing of the sheet with theslab without injury to said face.

2. A piezoelectric transducer comprising a pair of crystal slabs whichchange dimensions between two points along vibrating faces in responseto electrical forces, a sheet of yielding conducting material along saidvibrating faces, cementitious material joining said slabs to hold thesheet against said faces, characterized in that the sheet is embedded insaid cementitious material and has a series of ridges and valleys, saidseries extending parallel to said vibrating face with smooth, roundedarched portions held in partially flattened, yielding contact with saidvibrating faces so as to permit lengthwise flexing of the sheet with theslabs without injury to said faces.

References Cited in the file of this patent UNITED STATES PATENTS2,128,813 Gagle Aug. 30, 1938 2,423,922 Arndt July 15, 1947 2,440,064Arnold et a1 Apr. 20, 1948 2,615,946 Katzman Oct. 28, 1952 2,758,262Geisselsoder Aug. 7, 1956 FOREIGN PATENTS 254,646 Switzerland Dec. 16,1948

